The fifth seed Indo-Spanish pair overcame the fighting German-Czech pair 4-6 6-4 16-14 in one hour and 34 minutes in the quarter-finals.
Sania and Nuria were profligate as they squandered as many as eight breakpoints in the first set before conceding lead.
They lost serve in the second set too but broke the rivals twice to draw parity and stretch the issue to the match tie-breaker, which was a tight affair.
At the men's competition, running simultaneously, Mahesh Bhupathi and Rohan Bopanna have reached the quarter-finals after scoring a dominating 6-3 6-0 win over Chinese wild card pair of Mao-Xin Gong and Zhang Ze.